Low viscosity bottom paste applicator for bag machines



June 17, 1969 B. A. PETERSEN 3,450,099

LOW VISCOSITY BOTTOM PASTE APPLICATOR FOR BAG MACHINES Filed Aug. 17, 1967 I N VEN TOR.

139% #42, M, M ATTORNEYS v Burdette A. Petersen, Plymouth, Wis.,

United States Patent 3,450,099 LOW VISCOSITY BOTTOM PASTE APPLICATOR FOR BAG MACHINES assignor to H. G. Weber and Company, Inc., Kiel, Wis., a corporation of Wisconsin Filed Aug. 17, 1967, Ser. No. 661,380

Int. Cl. B05c 1/00, 1/16, J/02 US. Cl. 118212 6 Claims ABSTRACT OF THE DISCLOSURE Applicator for low viscosity paste, having a metering nozzle supplied with paste by a positive displacement adjustable metering pump. The nozzle deposits paste on a transfer roll at the rate of consumption rate of the paste along the region of engagement of a reverse angle doctor with the transfer roll. The doctor serves to maintain the face of the transfer roll clean and to accumulate paste on the roll in the form of a patch. A cam driven by an applicator roll i provided to periodically raise the doctor above the transfer roll, to allow a patch of paste to pass by the doctor to be transferred to an applicator sector on the applicator roll, applying paste to the inner and outer flaps of the bottoms of paper bags on the drum of the bag making machine.

Background 0] the invention Heretofore, paste has been applied to the inner and outer bottom flaps of bags on a bag making machine by a roll picking up paste from an open pot or container and a transfer roll partially immersed in the paste pot and completely loaded with paste about its periphery. Thi exposes more paste to the air than is necessary, resulting in drying and contaminating the paste. The paste is transferred by the transfer roll to a paste sector on an applicator roll and due to the low viscosity of the paste, the paste is slung about the bag making machine by the rotating paste sector. This waste paste is frequently slung onto underside parts of the bag, spoiling the bag and wasting paste in addition to making it necessary to frequently clean the machine.

Summary of the invention and objects The paste appliactor of the present invention reduces spoilage of bags and wasting of paste and reduces the need for frequently cleaning the machine and also eliminates contamination of the paste by metering paste directly to a transfer roll which supplies paste to a paste sector as fast as it is supplied to the transfer roll. A reverse angle doctor maintains the transfer roll clean while the metering nozzle lays down the paste on the transfer roll adjacent the line of contact of the doctor with the transfer roll. The paste deposited on the transfer roll builds up in the form of a patch of a circumferential length which is slightly shorter than the length of the paste sector on the paste applicator roll. The doctor is periodically raised above the surface of the transfer roll to accommodate the patch of paste to pass by the doctor onto the paste sector. The paste sector initially comes in contact with the bare transfer roll and then leads into the patch of paste on the roll. As the trailing end of the paste sector leaves the transfer roll, the adhesive patch has been used up. There, therefore, is little, if any, residue of paste to be feathered on the trailing end of the paste sector, with no paste to be slung by the paste sector.

The metering nozzle is supplied with paste by a positive displacement adjustable metering pump which supplies just enough paste to spread out to the width of the sector for each pasting operation, the width of which patch may be regulated by adjusting the flow of the positive displacement metering pump.

A principal object of the invention is to provide an improved form of paste applicator, arranged with a View towards eliminating wasting and contaminating paste in the pasting of the bottoms of paper bags.

Another object of the invention is to improve upon the applying of paste to the bottoms of paper bags on bag making machines, by metering a predetermined quantity of paste to a transfer roll and building up paste on the transfer roll in the form of a patch of less circumferential length than the circumferential length of the paste sector on the applicator roll, by the use of a reverse angle doctor, maintaining the surface of the applicator roll clean, and by providing means to raise the doctor above the surface of the applicator roll, to intermitently accommodate a paste patch to pass by the doctor, to be picked up by a paste sector on a mating applicator roll.

Another object of the invention is to improve upon the application of paste to the bottoms of paper bags by providing a metering nozzle for metering a flow of paste to a transfer roll at the rate of consumption of the paste, by using a reverse angle doctor, to doctor the transfer roll clean, and by utilizing cam and follower means for lifting the reverse angle doctor at predetermined intervals, to accommodate a patch of paste to pass thereby to be picked up by a paste sector on an applicator roll, applying paste to the bottom of the bag.

A still further object of the invention is to provide a novel and improved form of paste appliactor for bag making machines, in which a reverse angle doctor, doctors paste from a paste transfer roll and is intermitenty raised from the surface of the roll, to accommodate a patch of paste suflicient to paste the bottom of a single bag to pass thereby, and to be picked up by a paste sector on an applicator roll, for application to the bottom of the bag.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIGURE 1 is a diagrammatic view in side elevation of the forming drum of a bag making machine, and showing a paste applicator constructed in accordance with the principles of the present invention, for applying paste to the inner and outer flaps of the bottom of a bag on the forming drum; and

FIGURE 2 is a diagrammatic perspective view of the paste applicator shown in FIGURE 1 diagrammatically illustrating a bag on the forming drum of a bag making machine and showing the bag moving into position to pick up paste from the paste sector on the applicator roll, of the paste applicator.

In the diagrammatic illustration of the invention in the drawings, I have shown a forming drum 10 of a conventional bag making machine. The forming drum 10 is shown in FIGURE 1 as being mounted on a shaft 11, driven from a motor 12, through suitable reduction gearing (not shown) which may be of a conventional form, commonly used for rotatably driving the forming drums of bag making machines. The .forming drum 10 is shown in FIGURE 2 as having a partially formed paper bag 13 thereon, having a bottom 15 with inner and outer flaps 16 and 17 extending in opposite directions from the center line of the bottom, and in position to be engaged by a paste sector 18 on an applicator roll 19. The applicator roll 19 is power driven by a drive connection indicated generaly by reference character 20, for driving the paste sector from the aplicator roll in a direction opposite to the direction of rotation of the forming drum.

The paste sector 18 picks up paste from a transfer roll 21 driven in the same direction of rotation as the direction of rotation of the applicator roll 19, through a conventional drive connection 22, diagrammatically shown as driven from the means for rotatably driving the forming drum. A metering nozzle 23 having its inlet connected with a positive displacement adjustable metering pump 24 is provided to meter just enough paste to the transfer roll 21, to paste the flaps 16 and 17 of the bottom of the bag 13. The metering pump may be driven from the means for rotatably driving the forming drum through a conventional drive connection diagrammatically indicated by reference character 25. An adjustment means in the form of a knob 26, is shown as being provided to adjust the displacement of the metering pump in accordance with the quantity of paste required to successively supply the paste sector 18 with just enough paste to paste the bottom of a bag, each time the paste sector comes into engagement with the bottom of a bag. The adjustment means may be in the drive connection to the metering pump and may adjust a variable pitch pulley or like driving device.

A reverse angle doctor blade 27 is shown in FIGURES 1 and 2 as extending across the face of the transfer roll 21 adjacent the top thereof and adjacent the outlet from the metering nozzle 23. The reverse angle doctor blade 27 has opposite end portions 29 extending along opposite ends of the transfer roll, to maintain the ends of the transfer roll clean. A transverse rock shaft 30, extending parallel to the axis of the transfer roll 21, forms a support for the reverse angle doctor blade 27 and also forms a means for raising the doctor blade above the surface of the transfer roll to accommodate a predetermined thickness of paste on the transfer roll to pass thereby and be picked up by the paste sector 18. The rock shaft 30 is suitably journalled on the frame for the bag making machine, and has a lever arm. 31 extending upwardly of one end thereof. A tension spring 32 connected between the upper end of the lever arm 31 and a fixed abutment 33 is provided to bias the doctor blade in full contact with the face of the transfer roll 21, and to doctor the transfer roll clean, when paste is not required.

The reverse angle doctor blade 27 is raised above the face of the transfer roll 21 by a cam 35 on a shaft 36, forming a support and drive shaft for the applicator roll 19. The cam 35 is engaged by a follower 37 on the lower end of a lever arm 39, keyed or otherwise secured to the rock shaft 30 and depending therefrom. Thus, when it is required to apply a film of paste to the paste sector 18, the high portion of the cam 35 engaging the follower 37 will effect rotation of the rock arm 39 in a clockwise direction and raise the edge of the doctor blade 27 above the periphery of the transfer roll a distance suffrcient to accommodate a patch of paste on said transfer roll to pass by said doctor blade to be picked up by the paste sector 18. rotating in the same direction as the transfer roll. The rotation of the transfer roll and paste sector in the same directions permits the paste sector to pick up paste from the transfer roll and avoids the forming of a web when the paste sector separates from the transfer roll, which in turn leaves no loose paste to be slung by the paste sector.

The delivery of paste by the metering pump 24 may be regulated by the adjustment knob 26 to lay a patch of paste down on the periphery of the transfer roll adjacent the line of contact of the reverse angle doctor 27 therewith, which is no larger than the paste required by the paste sector 18. In regulating the quantity of paste delivered to the transfer roll, and the distance the doctor blade is raised above the periphery of the transfer roll to accommodate the paste to pass thereby, the paste delivered should be of such a quantity that the circumferential length of the patch of paste will be slightly shorter than the paste required by the paste sector. The paste then is allowed to flow sideways and spread out as wide as the sector.

In accordance with the teachings of the present invention, the circumferential length of the patch is attained by reverse angle doctor 27 operated by the cam 35 which may be interchanged with other cams for various bag surfaces. The width of the patch of paste on the applicator roll is regulated by the adjustable metering pump which is adjusted to meter just enough paste to spread along the transfer roll for the width of the paste sect-or.

Since the length of the patch of paste is slightly less than the peripheral length of the paste sector, the paste sector will initially come in contact with the bare transfer roll and then lead into the patch of adhesive so as to prevent a building up or scooping action of adsesive on the leading edge of the paste sector. As the trailing ends of the paste sector leave the transfer roll, the adhesive patch has already been used up, with a resultant minimum amount of residue or string to be feathered out on the trailing end of the paste sector. This prevents slinging of paste by the paste sector and in addition to substantially reducing paste waste also materially reduces cleanup time of the machine.

The anti-slinging feature also permits the use of inexpensive adhesives for bottom pasting, and since the paste is used as fast as it is supplied, the paste may be readily reheated to stimulate the tack of the paste and reduce the time required for the paste to set.

I claim as my invention:

1. In a paste applicator and in combination with a bag making machine having a rotatably driven bottom forming drum, carrying a paper bag for forming the bottom thereof;

a paste applicator roll having a cylindrical periphery and having a paste sector thereon extending radially outwardly of the periphery of said roll for applying a preselected paste pattern to the bottom of the a transfer roll for transferring paste to said paste sector;

means for driving said transfer rolling and paste sector in the same directions and at the same peripheral rates of speed,

doctor means in doctoring cooperation with said transfer roll and extending thereacross,

a metering nozzle having a discharge end disposed closely adjacent said doctor means for supplying a metered supply of paste to said transfer roll,

means for metering a predetermined supply of paste to said metering nozzle, and

other means operable by power and having operative connection with said doctor means for sequentially raising said doctor means a preselected distance above the face of said transfer roll to allow a preselected film of paste to pass thereby for transfer to said paste sector.

2. A paste applicator in accordance with claim 1,

wherein the doctor is a reverse angle doctor and extends entirely across the top surface of said paste applicator roll and along opposite sides thereof for damming up the paste deposited on said roll to spread across the surface thereof in the form of a thin film,

wherein means are provided for biasing said doctor into engagement with said transfer roll, and

wherein the means for raising said doctor above the surface of said transfer roll is driven in timed relation with respect to said paste applicator roll to raise said doctor a distance sufficient to supply a thin film of paste to said paste sector and move said doctor into doctoring cooperation with said transfer roll as said paste sector passes by said roll.

3. The paste applicator of claim 1,

wherein the means supplying paste to said nozzle means comprises a power driven metering pump, and wherein means are provided to vary the quantity of paste delivered by said pump.

4. In a bag making machine, a rotata'bly driven bag forming drum;

a paste applicator for applying paste to the bottom of -a traveling paper bag on said forming drum includin:

a paste applicator roll;

means driving said paste applicator roll in a direction opposite to the direction of rotation of said forming drum;

a paste sector on said applicator roll having a paste applicator face spaced above the surface thereof for applying paste to the inner and outer bottom flaps of the bottom of the bag;

a transfer roll engageable with said paste sector;

means for driving said transfer roll in the same direction of rotation as said paste sector;

a paste metering nozzle metering paste to said transfer roll,

a reverse angle doctor engageable with the face of said transfer roll and extending therealong and scraping paste from said transfer roll;

said paste metering nozzle having a discharge end closely adjacent said reverse angle doctor for metering paste thereto, and

means sequentially raising said doctor above the surface of said transfer roll during preselected phases in the cycles of rotation of said transfer roll, to supply a uniform film of paste to said paste sector, and to maintain the surface of said paste applicator roll clean. 5. A bag making machine in accordance with claim 4, wherein a power driven metering pump is provided to meter paste to said metering nozzle; and wherein means are provided to adjust the rate of metering paste from said nozzle. 6. A bag making machine in accordance with claim 4, wherein a metering pump is provided to meter paste to said metering nozzle; wherein means are provided to adjust the rate of metering paste to said nozzle by said pump; wherein cam and follower means are provided for sequentially raising said doctor above the surface of said transfer roll during preselected phases in the cycles of rotation of said transfer roll; and wherein said metering pump, said cam and follower means, said transfer roll and said appilcator roll are all driven by the means for driving said forming drum.

References Cited UNITED STATES PATENTS 2,102,984 12/1937 Von -Hofe 118-204 2,970,564 2/1961 Warner 118-259 XR WALTER A. SCHEEL, Primary Examiner. ROBERT I. SMITH, Assistant Examiner.

U.S. Cl. X.R. 938; 118-7 

